Guys, he took his UI down on purpose. Tracking down his character and harrassing him in-game trying to get the UI he obviously doesn't want to distribute anymore seems pretty inappropriate.

You might be right here Phanx, but on the other hand, he/she might be surprised and happy someone got in touch. I mean, asking a question isn't harassing as long as you leave the conversation if he/she says no. If you're really lucky he might help out in one way or another, but if he doesn't you're on your own.